Zero liquid discharge in mining and metallurgy Achema 2006 Ettlingen D. Gier

Presentation Outline GEA Organization GEA Filtration Wastewater in mining and metallurgy Conventional treatment Reverse Osmosis Design Operational Parameters

Organisational Structure GEA Customized Systems Process Equipment Process Engineering Plant Engineering  Process Engineering  Energy Technology  Mechanical Separation  Process Equipment  Dairy Farm Systems  Air Treatment  Refrigeration  Lurgi  Lurgi Lentjes  Zimmer

Process Engineering Division Major Companies of the Process Engineering Division mg engineering Niro A/S Niro Inc. Aeromatic-Fielder Barr-Rosin Collette NV Courtoy NV Niro Inc. GEA Wiegand GmbH GEA Liquid Processing Scandinavia GEA Kestner SAS GEA Messo GmbH GEA Jet Pumps GmbH Niro Pharma Systems Tuchenhagen Brewery Systems Tuchenhagen Dairy Systems Strategic Business Unit Filtration

GEA Filtration Organisation GEA Filtration (Technology Center – Niro Inc.) Europe GEA Liquid Processing Scandinavia A/S GEA Wiegand GmbH Scami Tuchenhagen SAS Americas Niro Inc Rest of the World Niro Inc. Australasia GEA Process Engineering (NZ) Ltd. GEA Process Engineering Australia Ltd.

Fields of operation GEA Filtration  Technology Leader  Global Player  Engage only in selected process segments  Dairy, Food & Beverage, Pharmaceuticals, Industrial  Provide a choice of state of the art membrane configurations – Spiral wound, Ceramic, stainless steel, hollow fiber etc.……..  Differentiate from others by providing a complete solutions - package of services to our customers  Pilot testing and process development capabilities  Process scale up  Complete system design and fabrication  Validation services  After sales service including replacement membrane services  Organic Growth  Opportunistic acquisition of niche separation technology companies

Dairy Industry Dairy  Milk  Cheese  Whey Products  Cultured Dairy products  Ice Cream  Water & Product Reclamation  Process Effluent treatment  Cleaning Chemical recovery

Food & Beverage  Vegetable products Fruit / Vegetable Juices  Grain Products Soy isolate, wheat proteins  Sugar, Starch and Sweetener Beet and Cane; corn, wheat, rice, Tapioca etc. products  Plant extracts Coffee, tea, herbal, oil seeds  Beverage Breweries, wineries, potable alcohol, soft drinks  Animal products Blood, gelatin, rendering, eggs, poultry  Fish & Seafood Products Proteins  Bio-food Products from Fermentation – e.g. organic acids  Water reclamation  Process Effluents  CIP Chemical recovery

Industrial Applications Industrial  Bio-chemicals Chemicals derived from Fermentation processes e.g. bio-plastics, bio-insecticides, bio-pesticides, organic acids  Distillery products Industrial alcohol, yeast  Enzymes  Pigments and dyes  Fine Chemicals  Water reclamation  Process Effluents  CIP Chemical recovery

Zero Discharge in Mining and Metallurgy  Elimination of liquid waste  Concentration of all pollutants in solid phase  Reduction of fresh water demand by reuse of purified wastewater  Protection of natural resources  Reduction of disposal cost

Technologies for Zero Discharge Involved Process Technologies and corresponding GEA company with specific Know-How:  Chemical / Physical water treatment : Messo  Conventional Filter technologies : Messo / Wiegand  Membrane Filtration: Messo / Wiegand / Niro  Evaporation: Messo / Wiegand / Niro  Crystallization : Messo / Kestner / Wiegand  Drying: Barr-Rosin / Niro

Wastewater in Mining and Metallury Water pollutants:  Heavy metals  Iron  Calcium, Magnesium  Trace elements: Strontium, Barium  Oils, Emulsions  Unspecific COD

Conventional treatment Conventional treatments:  Precipitation:Heavy metals  Oxidation:Iron  Oil-Skimmer, Flotation:Oils, Emulsions  Sedimentation  Filter press for dewatering of sludge's Limits:  Insufficient qualities for water reuse  Insufficient educts qualities for discharge due to tighter legislative regulations

Optimisation of conventional treatment Oxidation: Operation:Oxidation of iron and manganese Oxidation of heavy metals Target:Precipitation of the corresponding hydroxides

Optimisation of conventional treatment Precipitation:Optimization of precipitation (reaction time, addition of crystallization nuclei, addition of ferric chloride……) Lime softening (addition of hydrated lime) Ca(HCO 3 ) 2 + Ca(OH) 2 2 CaCO H 2 O Mg(HCO 3 ) Ca(OH) 2 Mg(OH) 2 + CaCO H 2 O Reduction of:- Carbonate hardness, barium, strontium, heavy metal- hydroxides, organics Soda-ash process: CaCl 2 + Na 2 CO 3 2 NaCl + CaCO 3 Reduction of:- Noncarbonate calcium hardness, silica, aluminum, iron

Optimisation of conventional treatment Filtration: Filter press: Sludge dewatering from precipitation, Optimization of filtrate quality (filter cloth, filtration pressure…) Fine filter: Fine filtration of precipitation overflow (backwash-filter, e.g. Fundabac-Filter)

Optimisation of conventional treatment Chemical pretreatment: Acidification: Acidification of reverse osmosis feed in order to rise solubility's Antiscalant: Addition of Antiscalant to rise precipitation concentrations

Reverse osmosis in Mining and Metallurgy Possible risks/limitations:  Suspended solids, Turbidity  Fouling:Iron, Alumina, Silica  Precipitation:Hardness (Ca, Mg), Bariumsulfat, Strontiomsulfat

Feed characteristics for Reverse Osmosis Process Feed and design characteristics:  Potential risk of suspended material in feed (high SDI-value)  Potential risk of fouling due to iron in feed  High salinity feed-stream  Low pH-feed  Elevated feed-temperatures are favorable (lower operational pressures, higher solubility's)  Extreme rise of osmotic pressure at higher recoveries

Membrane selection Membrane selection criteria:  Operational range of pH must be high  Larger feed-spacer: low impact of fouling (pressure drop) better cleanability  High nominal rejection in order to optimize permeate qualities (seawater membrane)  High pressure design for membrane (seawater membrane)

Design Considerations Design considerations:  Loop-Configuration is favorable to provide ideal cross-flow conditions for membrane elements  Booster-pumps are necessary to compensate rising osmotic pressures between stages  Conservative specific flux rates (approx. 15 lmh) to minimize fouling tendencies and increase operating times  Frequency controlled pressure pumps to minimize energy consumption  Safety considerations to provide maximum availability  Corrosion resistant materials due to high salt contents

Exemplary Flow diagramm

Sizing calculation of exemplary wastewater Feed Composition: Recovery Osmotic Pressure Filtration pressure NH mg/l 40 %11 bar 23 bar Na2.200mg/l 65 %19 bar 34 bar Cl400mg/l 80 %34 bar 48 bar SO mg/l Calculation based on High Rejection Seawater membrane at 40 °C filtration- temperature.

Confirmation of water composition by trials  Continuous operation of optimized pretreatment  Continuous operation of reverse osmosis  Cleaning trial  Membrane autopsy after trials  Concentrate out of membrane plant goes to further treatment: - Evaporation by falling-film evaporator with mechanical vapor recompression (MVR) - Crystallization in forced circulation evaporator

Exemplary pilotplant execution for pretreatment and reverse osmosis operation

Results from pilotisation Pilotisation Results: FeedPermeate Concentrate Total solids – ppm200 – 900 ppm – ppm Conductivity13,3 – 19,7 mS/cm300 – 900 µS/cm 80 – 120 mS/cm pH2,7 – 3,32,4 – 3,7 2,8 – 3,2 NTU0,18 – 0,450,1 – 0,5 0,3 – 1,7 NH – ppm<10 ppm – ppm Na900 – ppm1 – 90 ppm – ppm Cl370 – 480 ppm50 – 390 ppm 900 – ppm SO – ppm500 – ppm – ppm

Operational parameters Reverse osmosis Operational Parameters and consumptions: Feed Flow:100 m3/h Permeate Flow:80 m3/h Energy consumption:230 – 260 kWh Specific energy:2,9 – 3,25 kWh/m3 Membrane cost: €/a Citric acid (30 %):85 m3/a Caustic (NaOH, 30%):70 m3/a Na4EDTA:2.000 l/a Steam (during CIP):500 kg/h Antiscalant:2.600 kg/a

Prefiltration Rack

Reverse Osmosis Rack

Thermal Process 20 m3/h

Operational parameters Reverse osmosis Operational Parameters and Consumptions for Thermal Process: Feed Flow:22 m3/h Energy consumption MVR:560 kWh/h Consumption steam pre-heating:2.000 kg/h Consumption of steam or evaporation:3.200 kg/h Antiscalant:2.600 kg/a Distillate production thermal process: kg/h Distillate quality TDS 100 ppm Final Filter Cake approx kg/h

Process Flow Diagram Falling Film Evaporation (MVR) FC- Evaporator (TVR) Band filter